Calculators toolsUpdated July 2026
Free Compound Interest Calculator
Calculate how an investment or savings balance grows with compound interest, directly in your browser.
Free online tool
No signup
Direct download
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Enter details to calculate compound interest.
0Final balance
0Interest earned
Your numbers stay in your browser.
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How to calculate compound interest
- Enter the starting principal.
- Enter the annual interest rate and how often it compounds.
- Enter the number of years — the final balance and interest earned update instantly.
Why use this private compound interest calculator?
Your numbers stay in your browser. The calculation uses the standard compound interest formula A = P(1 + r/n)^(nt), so you can verify the result by hand.
Common use cases
- Estimate how a savings balance grows over time
- Compare annual vs. monthly compounding on the same investment
- Check how much interest an investment will earn by a target date
Frequently asked questions
Is this compound interest calculator free?
Yes, with no signup or watermark.
Are my numbers uploaded?
No. The calculation runs locally in your browser.
What compounding frequencies are supported?
Annually, semi-annually, quarterly, monthly, and daily.
Does this include regular monthly contributions?
No. This version calculates growth of a single starting principal only, not ongoing contributions.